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Pemberton Trail 50K Course Guide

The Pemberton Trail 50K is a fast desert ultra in McDowell Mountain Regional Park near Fountain Hills, just outside Phoenix. Two smooth, runnable loops, gentle rolling climbs, cool January mornings, and full Sonoran sun. I will walk you through the loop, then give you pacing and fueling for a fast, exposed 50K, plus free tools to dial in your own numbers.

⏵ Quick facts

The Pemberton Trail 50K at a glance

Date
Sat, January 23, 2027 (next edition)
Location
McDowell Mountain Regional Park, near Fountain Hills, AZ (Phoenix metro)
Distances
50K (two loops) and 25K (one loop)
The loop
The 15.4 mile Pemberton Trail, run as a loop
Elevation gain
Roughly 1,000 ft per loop, about 2,000 ft for the 50K
Terrain
Smooth, runnable Sonoran desert trail, gently rolling, fully exposed
Time limit
About 8 hours
Qualifier
A fast, popular first or PR 50K, not a Western States or UTMB qualifier

Note: the Pemberton Trail 50K is run on the 15.4 mile Pemberton loop in McDowell Mountain Regional Park, with the 50K covering two loops and the 25K one. Exact vert, aid station mileages, field caps, and cutoffs shift slightly year to year, so always confirm the date, distances, and rules on the official race page before you plan your race.

The course

The Pemberton Trail 50K runs the 15.4 mile Pemberton Trail loop through McDowell Mountain Regional Park, a Sonoran desert preserve in the Phoenix metro near Fountain Hills. The 50K is two laps of the loop, the 25K is one. The trail is smooth, well kept, and almost all runnable, with about 1,000 feet of gentle rolling gain per loop, roughly 2,000 feet across the full 50K, and the whole thing sitting low between about 1,850 and 2,500 feet.

A loop that climbs gently and gives it back

The Pemberton loop is a long, gradual, slightly rocky climb through the first part of the lap, and then a gentle downhill you can run that brings you back toward the start. No big mountain climbs, nothing technical to scramble over, just rolling desert with a handful of short rises that most people power hike to save the legs.

Since it is a loop, the 50K means doing the whole thing twice, and that is a gift for pacing. You learn exactly where the climbs and the runnable downhills are on lap one, then you run a smarter, more even lap two. The trap is that the smooth surface makes you want to bank time early. And banking time early is the quickest way to blow up in the exposed back half of lap two.

Exposure is the real difficulty

The terrain here is forgiving. The sun is not. The Pemberton Trail is open Sonoran desert with almost no shade, so once the January sun is up the course feels a good bit warmer than the air temperature says. On a fast 50K where you are running at a higher effort, that sun is the single biggest thing you are dealing with, more than the modest climbing.

So plan to work the sun the whole time. Start in layers you can shed, keep fluids and electrolytes going in even when the morning feels cool, and use the aid stations to top off and cool yourself down. The people who fade out here usually did it to themselves by under-drinking in the cool early miles, and then they pay for it under the midday sun.

Aid stations and cutoffs

There are aid stations roughly every 5 miles, and because it is a loop the start, finish, and 50K halfway point all sit at the same hub. So you are never far from water, electrolytes, and food, and you can stage anything you want at the start/finish between laps.

The overall limit is generous for the distance, around 8 hours for the 50K, which is easy to live with on a course this runnable. Still, carry enough fluid to cover the roughly 5 mile gaps between aid in the desert sun, and go confirm the exact cutoffs on the official race page before race day so you can build your pacing plan with a buffer.

Pacing strategy for the Pemberton Trail 50K

A fast, runnable 50K rewards even pacing and punishes the mile you banked early. The loop and the gentle terrain make this a real PR course, but only if you hold back when it feels easy.

Run an even or negative split across the two loops

Since the 50K is two identical laps, the cleanest plan is to run lap two as fast or faster than lap one. Pick a goal effort that feels almost too easy through the first loop, get your hydration and fuel settled, then let the back half come to you. Most blow-ups out here come from runners chasing a fast first loop on fresh legs and cool air, and then they come apart under the sun on loop two.

Use our free grade-adjusted pace calculator to turn your flat road or treadmill fitness into honest effort targets for the gentle Pemberton climbs and downhills, so you actually know what a sustainable rolling-desert pace is instead of guessing off a flat number.

Set a realistic finish goal

A well-paced runner can really PR the 50K here, so set a finish target that fits your fitness and the conditions. Hold back early, stay on top of fuel and fluid, and the runnable back half pays you back instead of breaking you.

Set that target with our race time calculator, which works the modest Pemberton vert into your projected finish, then reality-check it against a recent result with our race equivalent calculator so your goal is built on real fitness and not hope.

Respect the sun, not the altitude

There is no real altitude to deal with here. The course sits low in the desert, so your sea-level or home pace numbers carry straight over, unlike a high mountain ultra. The thing to pace around is the heat from all that exposure. As the sun climbs on loop two, run by feel and keep cooling and drinking, and your pace can hold even while the temperature goes up.

If you want a deeper read on how the desert sun should shape your effort and fueling, our heat training and acclimatization guide covers how to get your body ready for an exposed race like this.

Fueling strategy for the Pemberton Trail 50K

A fast 50K in exposed desert makes fueling and hydration matter as much as fitness. The sun is the thing that quietly wrecks otherwise well-trained runners, so plan for it from the cool first mile.

Carbs: fuel for a fast effort

A 50K is short enough that you run it at a higher intensity than a 100 miler, which means your engine wants steady carbohydrate the whole way. Aim for about 60 to 90 grams of carbohydrate per hour on a gut you have trained, leaning to the high end if you are racing it hard, and use a glucose-plus-fructose blend so you can take in more than a single sugar lets you.

Practice your exact hourly carb number on long runs so it is automatic on race day. Our guides on how many carbs per hour for an ultramarathon and how to build an ultramarathon fueling plan walk you through dialing this in.

Sodium and fluid: built for the desert sun

The exposed Sonoran trail can run your sweat losses up even on a cool-looking January day, so keep electrolytes coming and carry enough fluid to cover the roughly 5 mile gaps between aid stations. Cramping, a sloshy stomach, that wrung-out late-race feeling, those are usually fluid and sodium problems, not fitness problems. Our guide on how much sodium per hour for ultra running helps you set a target.

Dial in a plan with our free ultra fueling calculator. Put in your weight, your goal time, and the sun you expect, and it gives you a carb, sodium, fluid, and caffeine number per hour built for the Pemberton duration and conditions. Then go test it in training before race day.

⏵ Free calculators for this race

Run your Pemberton Trail 50K numbers with our free, no-signup tools, then let Summit Line tie them all back to your real fitness and this exact course.

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Train for the distance and conditions

The Pemberton Trail 50K makes a great first 50K or a PR target. These guides cover the training that matters most for a fast, exposed desert 50K: building to the distance, handling the sun, and pacing by effort.

⏵ Train for the Pemberton Trail 50K

Get a race-day plan dialed to YOUR fitness, this exact course profile, and your projected splits. Summit Line reads your real training, builds a fueling and pacing plan around the Pemberton loops and the desert sun, and tracks how your gut and legs handle the load, so race day is rehearsed instead of guessed.

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Pemberton Trail 50K FAQ

How hard is the Pemberton Trail 50K?

For a 50K this one sits on the easier, faster side. You run two loops of the smooth 15.4 mile Pemberton Trail in McDowell Mountain Regional Park, the terrain just rolls gently, and you only add up about 2,000 feet of climbing across the whole 50K. There are no big mountain climbs and nothing technical to scramble over, and that is exactly why people pick it for a first 50K and why it is a real PR course. The hard part is that the trail is wide open Sonoran desert with almost no shade. So the sun and how well you hold your pace, not the climbing, are what decide your day. And the roughly 8 hour cutoff gives you plenty of room.

How much climbing is in the Pemberton Trail 50K?

Each lap of the 15.4 mile Pemberton Trail has about 1,000 feet of gain, so the two-loop 50K comes out to roughly 2,000 feet, and the one-loop 25K is closer to 1,000 feet. None of it is one big climb. It is spread out across gently rolling ground. The first part of the loop is a long, gradual, slightly rocky climb, and the back half is a gentle downhill you can actually run, so you settle into a rhythm instead of grinding up walls.

How should I fuel for the Pemberton Trail 50K?

This is a fast 50K, which means you are usually working at a higher effort than you would in a long mountain ultra, so most people do well aiming for about 60 to 90 grams of carbohydrate per hour on a gut you have trained, leaning toward the high end if you are pushing it. The course is wide open desert, so honestly the things that matter most are your hydration and sodium. Plan to carry your own fluid between the aid stations, keep electrolytes going in even on a cool January morning, and practice your hourly carb number in training before you ever toe the line. Our free ultra fueling calculator builds you a carb, sodium, and fluid plan per hour for your goal time and the desert sun you are going to get.

What are the Pemberton Trail 50K cutoffs?

The 50K gives you a generous limit of about 8 hours, which is plenty on a course this runnable. Aid stations sit roughly every 5 miles, so you get regular spots to refill and reset. Still, go check the exact overall cutoff and any intermediate ones on the official race page for the current edition, then build your pacing plan with a comfortable buffer so the exposed back half of each loop never puts you behind the clock.

What is the weather like at Pemberton in January?

The race sits in the low Sonoran desert near Fountain Hills, between about 1,850 and 2,500 feet, so altitude does not come into play. Late January usually gives you cool mornings and mild, dry afternoons, and that is a big reason the date is so popular. The catch is the sun. The trail has almost no shade, so a clear midday warms up fast and feels a lot hotter than the air temperature would tell you. Dress for a cool start you can peel off, carry enough fluid, and respect the sun, even though there is no summer heat or altitude to worry about here.

Is the Pemberton Trail 50K a good first 50K?

Yes, it is one of the better first 50K picks in the Southwest. The course is smooth and runnable with nothing technical, the climbing is modest at around 2,000 feet, the loop means you are never far from aid or the start, and the cool January desert is about as kind as ultra weather gets. The two things to respect are the full sun and the urge to go out too fast on a course this runnable. Pace it by effort, fuel and drink on a schedule, and it makes a great first 50K or a real shot at a PR.

This guide is for planning and training purposes and reflects publicly available information about the Pemberton Trail 50K. Race details, including the date, distances, course, aid stations, and cutoffs, can change year to year. Always confirm the current specifics on the official race website before you train or travel.